Chapter
Rigby, J.K.
2004a. Classification. In R.M. Finks, R.E.H. Reid & J.K. Rigby, Volume 3: Porifera (Demospongea, Hexactinellida, Heteractinida, Calcarea). In R.L. Kaesler (ed.), Treatise on Invertebrate Paleontology, Part E, Porifera (Revised). The Geological Society of America, Inc. and The University of Kansas, Boulder, Colorado, and Lawrence, Kansas: 1-8.